Hiya, he will measure fron the sternal notch (the indent at the base of the neck in the middle), diagonally across to the nipple. Anything more than 21cm is classed as ptosis (droopiness), but the surgeon will advise if it is enough to warrant an uplift. Sometimes they will suggest a large implant to give a bit of a lift as well.
Good luck, you will be fine with Mr A! Take a list of questions to ask and write down the answers if you are nervous or you may forget afterwards! I did this and I felt like I was interviewing him but he was perfectly happy to answer everything x x
